ARTEMIS-4291 Add the "broker" tag in a consistent manner to all exported metrics.

Some scrapers, e.g. prometheus, add an "instance" tag. This value may not be the same as
the broker name, which results in these metrics becoming more difficult to match up with
the corresponding broker.

artemis-server/src/main/java/org/apache/activemq/artemis/core/server/metrics/MetricsManager.java

@@ -57,20 +57,23 @@ public class MetricsManager {
                          MetricsConfiguration metricsConfiguration,
                          HierarchicalRepository<AddressSettings> addressSettingsRepository) {
       this.brokerName = brokerName;
-      meterRegistry = metricsConfiguration.getPlugin().getRegistry();
-      Metrics.globalRegistry.add(meterRegistry);
+      this.meterRegistry = metricsConfiguration.getPlugin().getRegistry();
       this.addressSettingsRepository = addressSettingsRepository;
-      if (metricsConfiguration.isJvmMemory()) {
-         new JvmMemoryMetrics().bindTo(meterRegistry);
-      }
-      if (metricsConfiguration.isJvmGc()) {
-         new JvmGcMetrics().bindTo(meterRegistry);
-      }
-      if (metricsConfiguration.isJvmThread()) {
-         new JvmThreadMetrics().bindTo(meterRegistry);
-      }
-      if (metricsConfiguration.isNettyPool()) {
-         new NettyPooledAllocatorMetrics(PooledByteBufAllocator.DEFAULT.metric()).bindTo(meterRegistry);
+      if (meterRegistry != null) {
+         Metrics.globalRegistry.add(meterRegistry);
+         meterRegistry.config().commonTags("broker", brokerName);
+         if (metricsConfiguration.isJvmMemory()) {
+            new JvmMemoryMetrics().bindTo(meterRegistry);
+         }
+         if (metricsConfiguration.isJvmGc()) {
+            new JvmGcMetrics().bindTo(meterRegistry);
+         }
+         if (metricsConfiguration.isJvmThread()) {
+            new JvmThreadMetrics().bindTo(meterRegistry);
+         }
+         if (metricsConfiguration.isNettyPool()) {
+            new NettyPooledAllocatorMetrics(PooledByteBufAllocator.DEFAULT.metric()).bindTo(meterRegistry);
+         }
       }
    }
 
@@ -92,7 +95,6 @@ public class MetricsManager {
       builder.accept((metricName, state, f, description) -> {
          Gauge.Builder meter = Gauge
             .builder("artemis." + metricName, state, f)
-            .tag("broker", brokerName)
             .tag("address", address)
             .tag("queue", queue)
             .description(description);
@@ -109,7 +111,6 @@ public class MetricsManager {
       builder.accept((metricName, state, f, description) -> {
          Gauge.Builder meter = Gauge
             .builder("artemis." + metricName, state, f)
-            .tag("broker", brokerName)
             .tag("address", address)
             .description(description);
          gaugeBuilders.add(meter);
@@ -125,7 +126,6 @@ public class MetricsManager {
       builder.accept((metricName, state, f, description) -> {
          Gauge.Builder meter = Gauge
             .builder("artemis." + metricName, state, f)
-            .tag("broker", brokerName)
             .description(description);
          gaugeBuilders.add(meter);
       });

tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/plugin/JvmMetricsTest.java

@@ -72,13 +72,18 @@ public class JvmMetricsTest extends ActiveMQTestBase {
                                      .setJvmThread(thread)));
       server.start();
       boolean result = false;
+      String brokerTagValue = "";
       for (Meter.Id meterId : MetricsPluginTest.getMetrics(server).keySet()) {
          if (meterId.getName().startsWith(match)) {
             result = true;
+            brokerTagValue = meterId.getTag("broker");
             break;
          }
       }
 
       assertEquals(found, result);
+      if (found) {
+         assertEquals(brokerTagValue, server.getConfiguration().getName());
+      }
    }
 }

tests/integration-tests/src/test/java/org/apache/activemq/artemis/tests/integration/plugin/NettyMetricsTest.java

@@ -0,0 +1,67 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ * <br>
+ * http://www.apache.org/licenses/LICENSE-2.0
+ * <br>
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.activemq.artemis.tests.integration.plugin;
+
+import io.micrometer.core.instrument.Meter;
+import org.apache.activemq.artemis.core.config.MetricsConfiguration;
+import org.apache.activemq.artemis.core.server.ActiveMQServer;
+import org.apache.activemq.artemis.core.server.metrics.plugins.SimpleMetricsPlugin;
+import org.apache.activemq.artemis.tests.util.ActiveMQTestBase;
+import org.junit.Before;
+import org.junit.Test;
+
+public class NettyMetricsTest extends ActiveMQTestBase {
+
+   @Override
+   @Before
+   public void setUp() throws Exception {
+      super.setUp();
+   }
+
+   @Test
+   public void testNettyPoolMetricsPositive() throws Exception {
+      internalTestMetrics(true, true, "netty.pooled");
+   }
+
+   @Test
+   public void testNettyPoolMetricsNegative() throws Exception {
+      internalTestMetrics(false, false, "netty.pooled");
+   }
+
+   private void internalTestMetrics(boolean found, boolean pool, String match) throws Exception {
+      ActiveMQServer server = createServer(false, createDefaultInVMConfig()
+         .setMetricsConfiguration(new MetricsConfiguration()
+                                     .setPlugin(new SimpleMetricsPlugin().init(null))
+                                     .setNettyPool(pool)));
+      server.start();
+      boolean result = false;
+      String brokerTagValue = "";
+      for (Meter.Id meterId : MetricsPluginTest.getMetrics(server).keySet()) {
+         if (meterId.getName().startsWith(match)) {
+            result = true;
+            brokerTagValue = meterId.getTag("broker");
+            break;
+         }
+      }
+
+      assertEquals(found, result);
+      if (found) {
+         assertEquals(brokerTagValue, server.getConfiguration().getName());
+      }
+   }
+}